沉积盆地超深层有机- 无机复合生烃机理及地质模式

全球范围内超深层油气的不断发现，对经典的生烃理论提出了挑战，外源氢加入的有机-无机复合生烃过程引起了广泛关注。基于地质观察统计数据，分子氢在沉积盆地中分布广泛，形成机制复杂。在地质环境中，水和水-岩反应、深部流体等途径产生的无机氢是最主要的外部氢源。可控加氢模拟实验揭示了沉积盆地的氢逸度水平是调控烃类产物生成的重要因素之一，并且干酪根的加氢裂解是沉积盆地中易于发生的生烃过程。外源氢介入生烃过程的前提是环境氢逸度大于沉积有机质本身的氢逸度，其有效范围受生烃母质化学组成和结构的制约，约起始于生油高峰之后，约终止于沉积有机质H/C=0.3之时。亦即，有机-无机复合生烃作用是沉积盆地超深层生烃的有效途径。在其有效发生的范围内，油气资源类型依然由生烃母质类型(化学组成和结构)、成熟度和受热历史等因素决定，具有明显的阶段性和不同于经典理论的生烃模式。外源氢的参与，在成熟阶段可小幅度提升生油产率；在高—过成熟阶段可显著增加天然气产率；在高成熟阶段，加氢脱烷基作用最大可增加50%的轻质油/凝析油产率；在过成熟阶段，加氢脱甲基-开环作用最大可增加约5倍甲烷产率。有机-无机复合生烃模式的确立，丰富了传统生...

Hydrocarbon generation mechanism via the organic- inorganic interaction pathway and its geological pattern in ultra- deep sedimentary basins

The continuous discovery of ultra- deep oil and gas around the world challenges the classical theory of hydrocarbon generation. The hydrocarbon generation process with exogenous hydrogen from organic- inorganic interactions has attracted wide attention. Based on the statistical data of geological observations, molecular hydrogen is widely distributed in sedimentary basins and its formation mechanism is complex. In geological environments, inorganic hydrogen derived from water, water- rock reactions and deep fluids is the main external source. Controlled hydrogenation simulation experiments reveal that the level of hydrogen fugacity in sedimentary basins is one of the essential factors regulating hydrocarbon generation, and the hydrocracking of kerogen is a preferential pathway for the hydrocarbon generation process in sedimentary basins. The premise of exogenous hydrogen participating in hydrocarbon generation is that the environmental hydrogen fugacity is greater than that of sedimentary organic matter. The range of this effect is constrained by the chemical composition and the structure of kerogen, and it probably starts after the peak of oil generation and ends approximately when the H/C of sedimentary organic matter is less than 0. 3. This demonstrates that hydrocarbon generation via organic- inorganic interactions is an effective pathway for hydrocarbon generation in ultra- deep strata of sedimentary basins. Within the effective range, the types of oil and gas resources are still determined by factors such as the types of kerogen (chemical composition and structure), maturity and heating history, with obvious stages and hydrocarbon generation modes different from the classical theory. With the participation of exogenous hydrogen, the oil generation yield can be slightly promoted in the mature stage and be significantly enhanced in the high- over maturity stage. Moreover, in the high- maturity stage, the hydrodealkylation reaction can increase the yield of light/condensate oil up to 50%, and in the over- maturity stage, the demethylation- ring opening reaction can increase the methane yield by approximately 5- fold. The new hydrocarbon generation model via the organic- inorganic interaction pathway expands the connotation of traditional hydrocarbon generation theory, establishes the theoretical foundation for ultra- deep oil and gas generation, and expands the vision of oil and gas exploration.